toString method
A string representation of this object.
Some classes have a default textual representation,
often paired with a static parse function (like int.parse).
These classes will provide the textual representation as
their string representation.
Other classes have no meaningful textual representation
that a program will care about.
Such classes will typically override toString to provide
useful information when inspecting the object,
mainly for debugging or logging.
Implementation
@override
String toString() {
final parts = <String>[];
if (source != null) parts.add('source=$source');
if (medium != null) parts.add('medium=$medium');
if (campaign != null) parts.add('campaign=$campaign');
if (term != null) parts.add('term=$term');
if (content != null) parts.add('content=$content');
return 'UTMParameters(${parts.join(', ')})';
}